1. Field of the Invention
The invention relates to an apparatus for supplying a therapeutic oxygen gas.
2. Description of the Related Art
In treatments for respiratory system diseases such as pulmonary emphysema or chronic bronchitis, oxygen inhalation is known as one of the most effective treatments. In oxygen inhalation therapy, a therapeutic oxygen gas, such as oxygen gas or an oxygen enhanced gas which may be produced by separating nitrogen gas from air, is supplied to the patient with a therapeutic oxygen gas supplying apparatus.
Conventional therapeutic oxygen gas supplying apparatuses supply a therapeutic oxygen gas intermittently, in synchronization with the respiration of a patient, at a constant volume for each respiration. The respiratory frequency, however, is not constant. When the respiratory frequency is increased, in particular when tachypnea is presented, if the therapeutic oxygen gas supplying apparatus supplies the therapeutic oxygen gas at a constant volume for each respiration, dyspnea will result.